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perf(line numbers): some improvements based on the suggestions
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Li Guanglin committed Aug 24, 2023
1 parent a6712c1 commit 26f33c1
Showing 1 changed file with 83 additions and 102 deletions.
185 changes: 83 additions & 102 deletions app/src/main/java/net/gsantner/markor/frontend/textview/HighlightingEditor.java
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Original file line number Diff line number Diff line change
Expand Up @@ -34,11 +34,6 @@
import net.gsantner.opoc.wrapper.GsCallback;
import net.gsantner.opoc.wrapper.GsTextWatcherAdapter;

import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

@SuppressWarnings("UnusedReturnValue")
public class HighlightingEditor extends AppCompatEditText {

Expand Down Expand Up @@ -216,8 +211,11 @@ public void setLineNumbersEnabled(final boolean enable) {
post(this::invalidate);
}
_numEnabled = enable;
if (!_numEnabled) {
if (_numEnabled) {
_lineNumbersDrawer.startLineTracking();
} else {
_lineNumbersDrawer.stop();
_lineNumbersDrawer.stopLineTracking();
}
}

Expand Down Expand Up @@ -476,94 +474,83 @@ static class LineNumbersDrawer {
private final Rect _visibleArea = new Rect();
private final Rect _lineNumbersArea = new Rect();

private int _startNumber = 1;
private int _maxNumber = 1; // to gauge gutter width
private int _maxNumberDigits;
private int _lastMaxNumberDigits;
private int _lastLayoutLineCount;
private float _lastTextSize;
private int _numberX;
private int _gutterLineX;
private final List<Integer> _lineIndex = new ArrayList<>(); // Index of layout lines currently being drawn
private int _gutterX;
private float _oldTextSize;
private final int[] _startLine = {0, 1}; // {line index, actual line number}

// Current line numbers area
// Note: the distance between the top and bottom = 3 * height of visible area
// In order to reduce the frequency of refreshing parameters of line numbers,
// the line numbers are drawn on previous page, current page and next page every time
private int _top;
private int _bottom;
private final GsTextWatcherAdapter lineTrackingWatcher = new GsTextWatcherAdapter() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
_maxNumber -= TextViewUtils.countChar(s, start, start + count, '\n');
}

@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
_maxNumber += TextViewUtils.countChar(s, start, start + count, '\n');
}
};

public LineNumbersDrawer(AppCompatEditText editor) {
public LineNumbersDrawer(final AppCompatEditText editor) {
_editor = editor;
_editor.getLocalVisibleRect(_lineNumbersArea);
_paint.setTextAlign(Paint.Align.RIGHT);
_defaultPaddingLeft = editor.getPaddingLeft();

_editor.addTextChangedListener(new GsTextWatcherAdapter() {
private final Pattern pattern = Pattern.compile("\n");
private Matcher matcher;

@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
if (after == 0 && count > 0) {
CharSequence deleted = s.subSequence(start, start + count);
matcher = pattern.matcher(deleted);
while (matcher.find()) {
_maxNumber--;
}
}
}

@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
if (before == 0 && count > 0) {
CharSequence added = s.subSequence(start, start + count);
matcher = pattern.matcher(added);
while (matcher.find()) {
_maxNumber++;
}
}
}
});
}

public void setTextSize(float textSize) {
if (_lastTextSize != _paint.getTextSize()) {
_lastTextSize = _paint.getTextSize();
}
public void setTextSize(final float textSize) {
_paint.setTextSize(textSize);
}

public int getNumberDigits(int number) {
if (_lastMaxNumberDigits != _maxNumberDigits) {
_lastMaxNumberDigits = _maxNumberDigits;
public boolean isTextSizeChanged() {
if (_paint.getTextSize() == _oldTextSize) {
return false;
} else {
_oldTextSize = _paint.getTextSize();
return true;
}
}

if (number < 10) {
public boolean isMaxNumberDigitsChanged() {
final int oldDigits = _maxNumberDigits;

if (_maxNumber < 10) {
_maxNumberDigits = 1;
} else if (number < 100) {
} else if (_maxNumber < 100) {
_maxNumberDigits = 2;
} else if (number < 1000) {
} else if (_maxNumber < 1000) {
_maxNumberDigits = 3;
} else if (number < 10000) {
} else if (_maxNumber < 10000) {
_maxNumberDigits = 4;
} else {
_maxNumberDigits = 5;
}
return _maxNumberDigits;
return _maxNumberDigits != oldDigits;
}

public boolean isOutOfLineNumbersArea() {
if (_visibleArea.top > _lineNumbersArea.top && _visibleArea.bottom < _lineNumbersArea.bottom) {
return false;
} else {
// If current visible area is out of line numbers area, line numbers area will be updated
_lineNumbersArea.top = _visibleArea.top - _visibleArea.height();
_lineNumbersArea.bottom = _visibleArea.bottom + _visibleArea.height();
return true;
}
}

public void startLineTracking() {
final CharSequence text = _editor.getText();
_maxNumber = TextViewUtils.countChar(text, 0, text.length(), '\n') + 1;
_editor.removeTextChangedListener(lineTrackingWatcher);
_editor.addTextChangedListener(lineTrackingWatcher);
}

public void stopLineTracking() {
_editor.removeTextChangedListener(lineTrackingWatcher);
}

/**
* Draw line numbers.
*
Expand All @@ -580,52 +567,47 @@ public void draw(final Canvas canvas) {
return;
}

final int offsetY = _editor.getPaddingTop();
final int layoutLineCount = layout.getLineCount();

// Only if the visible area is out of current line numbers area or the layout line count changed
// We make a single pass through the text to determine
// 1. Start line number to be drawn at present;
// 2. Index of layout lines to be drawn at present.
if (isOutOfLineNumbersArea() || layoutLineCount != _lastLayoutLineCount) {
_lastLayoutLineCount = layoutLineCount;
_startNumber = 1;
_lineIndex.clear();
_top = _visibleArea.top - _visibleArea.height();
_bottom = _visibleArea.bottom + _visibleArea.height();
for (int i = 0; i < layoutLineCount; i++) {
final int start = layout.getLineStart(i);
if (start == 0 || text.charAt(start - 1) == '\n') {
final int y = layout.getLineBaseline(i);
if (y > _bottom) {
break;
} else if (y < _top) {
_startNumber++;
} else {
_lineIndex.add(i);
}
}
}
}

// Only if the text size or the max line number of digits changed
// Update the gutter parameters and set padding
if (_paint.getTextSize() != _lastTextSize || getNumberDigits(_maxNumber) != _lastMaxNumberDigits) {
final int width = Math.round(_paint.measureText(String.valueOf(_maxNumber)));
_numberX = LINE_NUMBER_PADDING_LEFT + width;
_gutterLineX = _numberX + LINE_NUMBER_PADDING_RIGHT;
_editor.setPadding(_gutterLineX + 10, _editor.getPaddingTop(), _editor.getPaddingRight(), _editor.getPaddingBottom());
// Only if the text size or the max line number of digits changed,
// update the gutter's parameters and reset padding
if (isTextSizeChanged() || isMaxNumberDigitsChanged()) {
_numberX = LINE_NUMBER_PADDING_LEFT + Math.round(_paint.measureText(String.valueOf(_maxNumber)));
_gutterX = _numberX + LINE_NUMBER_PADDING_RIGHT;
_editor.setPadding(_gutterX + 10, _editor.getPaddingTop(), _editor.getPaddingRight(), _editor.getPaddingBottom());
}

// Draw the gutter line
// Draw the right border of the gutter
_paint.setColor(Color.LTGRAY);
canvas.drawLine(_gutterLineX, _top, _gutterLineX, _bottom, _paint);
canvas.drawLine(_gutterX, _lineNumbersArea.top, _gutterX, _lineNumbersArea.bottom, _paint);

int i = _startLine[0], number = _startLine[1];
// Only if the visible area is out of current line numbers area,
// update the parameters of the line numbers which will be drawn
if (isOutOfLineNumbersArea()) {
i = 0;
number = 1;
_startLine[0] = -1;
}

// Draw the line numbers
// Draw the line numbers (on the previous, current and next page every time)
_paint.setColor(Color.GRAY);
final int size = _lineIndex.size();
for (int i = 0; i < size; i++) {
canvas.drawText(String.valueOf(_startNumber + i), _numberX, layout.getLineBaseline(_lineIndex.get(i)) + offsetY, _paint);
final int count = layout.getLineCount();
final int offsetY = _editor.getPaddingTop();
for (; i < count; i++) {
final int start = layout.getLineStart(i);
if (start == 0 || text.charAt(start - 1) == '\n') {
final int y = layout.getLineBaseline(i);
if (y > _lineNumbersArea.bottom) {
break;
}
if (y > _lineNumbersArea.top) {
if (_startLine[0] < 0) {
_startLine[0] = i;
_startLine[1] = number;
}
canvas.drawText(String.valueOf(number), _numberX, y + offsetY, _paint);
}
number++;
}
}
}

Expand All @@ -634,9 +616,8 @@ public void draw(final Canvas canvas) {
*/
public void stop() {
if (_editor.getPaddingLeft() != _defaultPaddingLeft) {
_maxNumberDigits = 0;
// Reset padding without line numbers
_editor.setPadding(_defaultPaddingLeft, _editor.getPaddingTop(), _editor.getPaddingRight(), _editor.getPaddingBottom());
_maxNumberDigits = 0;
}
}
}
Expand Down

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